Grace Hopper

Hopper is believed to have concieved the concept of the
compiler with the A-0 in 1952. She also developed the
first commercial high-level language, which eventually
evolved into COBOL. She worked on the Mark I computer
with Howard Aiken and with BINAC in 1949.

She is credited with having coined the term "debug", and the
adage "it is always easier to ask forgiveness than it is to
get permission" (with various wordings), which has been the
guiding principle in sysadmin decisions ever since.